The goal of this project is to push the resolution limit of HP gas MRI as far as possible in resolving the microstructure of the airways. We will be explicitly completing Specific Aim 7 for the grant (In vivo MRM of Environmental Lung disease 1R01 Hl 55348-01). We will employ projection encoding in conjunction with a surface coil. We will use selective infusion of the gas to maximize the transfer of signal into the resulting image. Phase 1 will use nonselective PR followed by aniostropic 3DPR.